Identification of differentially expressed genes in seeds of two near-isogenic Brassica napus lines with different oil content.

The regulation of seed oil synthesis in rapeseed is largely unknown. In this study, we compared the gene expression during seed development between two lines of Brassica napus with a 10% difference in oil content. We isolated the immature seeds 15 and 25 days after flowering at periods preceding and including the major accumulation of storage oils and proteins. The differentially expressed gene clones between the two rape lines were isolated by subtractive suppression hybridization (SSH). All SSH clones were arrayed and screened by dot blot hybridization, followed by RT-PCR analysis for selected clones. A total of 217 cDNA clones corresponding to 30 genes were found to have a high expression in seeds with high oil content. Six genes were highly expressed in seeds with low oil content. Northern blot and enzyme activity analysis demonstrated a change in expression pattern of several genes. The results provide information on gene-encoding factors responsible for the regulation of oil synthesis. The possible role of these genes in seeds is discussed. The genes in this study may be suitable as novel targets for genetic improvement of seed oil content and may also provide molecular markers for studies of rape breeding.